In the first part of this article series, “Muscle Contractions: Part 1: Different Types,” the various types of muscle contractions and their nomenclatures were discussed. The second part of the series, "Muscle Contractions: Part 2: How to Use Them – Theory,” compared the muscle contractions and discussed some of theory behind applying this knowledge into practical applications. In this final part of the series, more practical examples for specific uses are given.
As a point of note: The author’s key philosophy is “how to think, not what to think,” as such only general examples are provided rather than detailed templates and programs. In essence there is no one program or principal that can be applied to all, and every coach / trainer needs to consider the conditioning requirements of the individual whenever devising training requirements.
With this in mind, this article will look at how to apply the developed knowledge on muscle contractions and provides examples for general training, improving performance, strength/power training, and finally rehabilitation.
Maximize time under tension by following the force-generating profile of the contractions. That is, eccentric contractions being stronger than isometric contractions, which are in turn stronger than concentric contractions.
Repetition speed of 3-2-1 = 3 seconds eccentric - 2 seconds isometric - 1 second concentric.
As Delayed Onset Muscle Soreness (DOMS) can be de-motivating for novices. Contraction profiles can be designed to minimize its development. That is, decreased eccentric contractions in favour of concentric contractions.
Repetition speed of 1-1-2 = 1 second eccentric - 1 second isometric - 2 seconds concentric.
Where clients are too weak to perform a movement, the movement can be rehearsed by again following the force-generating profile of the contractions. That is, eccentric contractions being stronger than isometric contractions, which are in turn stronger than concentric contractions.
- Start in the push-up position (on toes).
- Lower eccentrically for 2 seconds.
- Hold isometrically in bottom position for 1 second and lower knees to ground.
- Raise concentrically with knees on ground for 1 second.
- Lower eccentrically over 2 seconds with one leg.
- Hold isometrically for one second as “free” limb is placed back on the foot platform.
- Raise concentrically over 1 second using both legs.
The same considerations can be given to more advanced clients, along the premise of “forced repetitions”:
- Client performs as many chin-ups as possible (e.g., 6 repetitions).
- The trainer assists the client on the concentric phase.
- Client holds isometrically in “up” position for 1 second.
- Client lowers eccentrically for 1-2 seconds.
If the client will have a few days off (e.g., Friday session with next session on Monday), increased eccentric training can be used to increase resting metabolic rate for up to 48 hours post-session (Remember, this will also include DOMS). For example:
- Set 1: 2-1-2 repetition speed = 2 seconds concentric - 1 second isometric - 2 seconds eccentric.
- Set 2: 1-1-3 repetition speed = 1 second concentric - 1 second isometric - 3 seconds eccentric.
- Set 3: 0-0-3 repetition speed = Jump up and eccentrically lower over 3 seconds.
Improving General Performance
Isometric contractions use less energy than dynamic contractions. Therefore, improving isometric stabilization strength by reducing movement in given joints may increase energy available for movements at other joints. For example, you may note that during maximal effort push ups, often the body (trunk and/or shoulders) begins to shake. This occurs as a resulting loss of isometric stabilization, causing a rapid alternation between concentric and eccentric contractions in an attempt to provide the required stabilization. Isometric training examples include:
- Using an isometric prone (“plank”) hold in a training program to increase push up performance.
- Using deep neck flexor and cervical extensor isometric contractions to minimize head movement during running (sprinting and longer distance).
Using machines to perform isokinetic movements (and using machines in general) to limit the amount of “functionality” of a movement by limiting the movement to only one degree of freedom.
- For example, compare the freedom of movement allowed in a machine squat versus a free weight, forward jumping squat, or squat with a push press.
Strength and Power Training
Increasing eccentric strength may improve concentric performance for a given lift. If more “energy” is saved when lowering, more can be transferred back to the concentric part of the lift. Eccentric strength can be improved in two ways:
Example 1: Increased eccentric loading using bench press.
- Set 1 & 2 = Bench press with a 1-1-1 repetition speed (1 second eccentric - 1 second isometric - 1 second concentric).
- Set 3 = Bench press with a 3-1-1 repetition speed (3 seconds eccentric - 1 second isometric - 1 second concentric).
Example 2: Eccentric-only training using bench press.
- Set 1 & 2 = Bench press with a 1-1-1 repetition speed (1 seconds eccentric - 1 second isometric - 1 seconds concentric).
- Set 3 = Bench press with a 120% 8 RM load (load being 20% heavier than the load for 8 repetitions maximum) using a 2-0-0 repetition speed (2 seconds eccentric, lifted up by spotter/s (note “lifted up” not “helped to lift up,” so spotters do ALL the isometric/concentric range work).
Increased eccentric strength can also improve explosive power. By increasing eccentric strength, more energy is stored during a rapid eccentric movement prior to the return transfer of this energy back into the concentric movement.
If the client has a dedicated weak point (“sticking point”) in an exercise movement, isometric contractions can be useful at improving strength at that range.
- Example 1: Push up failure point at 90 degree of horizontal shoulder extension & elbow extension.
- Isometric holds to failure: Push up to weak point and hold until technical failure.
- Example 2: Push up failure point at 90 degree of horizontal shoulder extension & elbow extension.
- Maximal Isometric contractions: Push up to weakest point in push up and have a partner apply resistance to meet your concentric attempt to continue the movement. (So you attempt to concentrically push through your weak point with a maximal effort while your partner prevents you from moving by applying load to your upper back). Work to technical failure.
With the primary function of isokinetic machines being to maintain a constant velocity, angular velocity of the isokinetic movements is typically low. The application of this form of training to power, which is typically fast velocity based, is questionable.
As isokinetic machines aim at maintaining a constant velocity, training acceleration (punching a pad), acceleration – deceleration patterns (kicking a ball – accelerate to develop force for kick, then decelerate to protect the joint at end range), and segmental force velocity patterns (e.g., the chest/shoulders to elbows to wrist and fingers in a throw – development and “passing” of velocity from one joint to the next along the kinetic chain with each link getting faster), is very difficult.
Because eccentric contractions are stronger than isometric or concentric contractions, eccentric contractions can be used in rehabilitating clients with notable muscle weakness (for example, progressing from Grade 2 to Grade 3 and then strengthening through to Grade 4 and 5) with the subsequent introduction of isometric and later concentric contractions.
||No muscle contraction felt
||Evidence of muscle contraction on palpitation (No joint ROM)
||Perform movement in gravity eliminated ROM (e.g., Side lying hamstring curl)
||Can perform movement against gravity (e.g., Prone lying hamstring curl)
||Can perform movement against gravity and some external resistance
||Can perform movement against gravity and a large amount of external resistance
As eccentric contractions can withstand higher loads, their use in training “shock absorbing” or “weight accepting” muscles is of importance for injury prevention as well as preventing a recurrence of overuse injuries.
- E.g., Achilles Tendinopathy rehabilitation: Ankle heel drops (rapid eccentric contractions of the Achilles tendon).
It is important to remember the client’s deceleration requirements. For athletes (professional or recreational) who are recovering from a stretch-related injury (E.g., hamstring muscle tear when kicking a ball), eccentric contractions can be extremely important. When kicking a ball, for example, the muscles must decelerate the limb rapidly after having developed force to kick the ball.
- For example, for a water polo player recovering from a shoulder injury, a functional return to throwing a ball is important. So too, however, is the need to catch and control the ball. While throwing the ball has an acceleratory pattern, catching and controlling a ball can have a deceleration pattern. As such rehabilitation exercises should not just include throwing (e.g., with a medicine ball), but should include catching as well.
The same considerations can be given to weight acceptance requirements with movement examples including: landing from a ski jump, moguls skiing, gymnastic or jump landings, downhill running, etc. As an example, for jump landing using a squat progression (NOTE: For brevity, the progression sequence has been simplified to several points along a progressive continuum):
- Squats: 3 Sets of 2-1-2 (2 seconds eccentric - 1 second isometric - 2 seconds concentric)…progressing to:
- Squats: 1-3 Sets of 4-1-2 (4 seconds eccentric - 1 second isometric - 2 seconds concentric)…progressing to:
- Jump Squats: 3 Sets of 2-0-2 (2 seconds eccentric weight acceptance from landing - immediate turn around to 1 second concentric - back into jump).
Just as consideration of the client’s deceleration and weight acceptance requirements are considered, so too must the isometric requirements. For example, many everyday clients will find that their forearms, which are performing isometric contractions, are fatigued during a seated row before the prime moving muscles of the back. Clients recovering from wrist joint or forearm muscle injuries must retrain these muscles to perform isometric contractions under force. This training can be applied as part of global training (e.g., performing a biceps curl or seated row) rather than just holding an isometric forearm contraction. The intent of the training must, however, be based on the isometric training requirements (e.g., the forearm muscles rather than the muscles of the back during a seated row, so no wrist straps, or grip enhancing devices, etc.). Examples include:
- Isometric forearm strength—endurance developed while performing a biceps curl or seated row.
- Isometric Erector Spinae strength—endurance developed while performing a squat or lunge (with reduced loads).
- Isometric Deep Neck Flexor activation—endurance developed while performing a sit up.
- Isometric Transverse Abdominal activation—endurance developed while performing a push up (ensuring that intensity is not so high as to globally activate the external obliques in an overriding manner).
Where hypertension or high blood pressure is a risk, isometric contractions should be minimized, especially in large muscle groups. So while isometric forearm contractions, like those used to stabilize the wrist in a seated row, may raise the client’s blood pressure minimally, isometric squat holds should be avoided. Consideration should also be given to the currently popular long prone holds (“plank”), although this author has yet to find any research on the impact of this exercise on blood pressure.
Isokinetic assessments can be useful for players when assessing a return to training ability IF pre-injury assessments have been conducted. While these assessments are not functionally-specific, they provide an assessment of movement through a joint in a manner that minimizes the ability for the athlete/client to “cheat” using compensation patterns to complete the movement.
- The use of a Kin Com Isokinetic Dynamometer knee extensor assessment pre- and post-knee reconstruction surgery. (NOTE: The post-surgery assessments are only conducted when the patient is nearing a return to sport, not as an early re-strengthening assessment, as these assessments are maximal.)
Isokinetic training machines can be useful when retraining movements and velocity must be controlled (thereby reducing the need for a break force at end range). Dynamic athletes (or clients) in particular, who are used to generating increasing force/speed with exercise movements, can therefore be trained initially in a controlled velocity manner.
It is important to remember that the rehabilitation continuum is a continual and evolving process, from initial injury through to optimal force performance. As such, where one training method (such as isokinetic machines) may be useful at one point in the continuum, it may not be appropriate at another.
A final key consideration with these examples is that they do not account for other variables including: strength curves, force-velocity curves, and length-tension curves.
In conclusion, over the three articles in this series, we have looked at how muscles can perform various types of contractions. Each of these contractions comes with their own specific characteristics, strengths, and weaknesses. For a training program to be most effective, the prescribing practitioner needs to understand not only the names and types of muscle contractions, but their characteristics and how best to apply the contractions to meet training needs and goals.
- Williams, H. (2008). Eccentric Training (Online). Personal Training on the Net.
- Parracino, L. (2004). Eccentric vs. Isometric vs Concentric Load (Online). Personal Training on the Net.